Symfony tutorials, tips and hidden gems

Below are a number of tutorial and informative articles for the Symfony framework.
Hopefully they will be useful in your Symfony journey.
If you have any questions, please feel free to comment on the specific post and I will do my best to respond
in a timely manner.

This issue occurs when Symfony2 tries to serialize an entity, often in a relationship when an entity has an ArrayCollection. Simple answer: Change private fields to protected so they are not hidden from the serializer!